kempo vs kenpo

[lpred37]

Is there a difference between kempo and kenpo? 

not really 

spelled with an M usually means  someone is [usually Japanese stylists] trying to differentiate themselves from American-style that usually spelled with an N

the Japanese styles usually, when they use the word Kempo, usually mean the empty hand, portion of a much more comprehensive art or Ryu

the American system that started with James Matosi ., through William Chow, to Ed Parker is usually spelled with N

just a side note, when it spelled in Kanji there's no difference